From: Ayushi Makhija quic_amakhija@quicinc.com
[ Upstream commit 50935044e58e563cdcfd556d62f27bc8744dd64e ]
Use gpiod_set_value_cansleep() instead of gpiod_set_value() to fix the below call trace in the boot log:
[ 5.690534] Call trace: [ 5.690536] gpiod_set_value+0x40/0xa4 [ 5.690540] anx7625_runtime_pm_resume+0xa0/0x324 [anx7625] [ 5.690545] __rpm_callback+0x48/0x1d8 [ 5.690549] rpm_callback+0x6c/0x78
Certain GPIO controllers require access via message-based buses such as I2C or SPI, which may cause the GPIOs to enter a sleep state. Therefore, use the gpiod_set_value_cansleep().
Signed-off-by: Ayushi Makhija quic_amakhija@quicinc.com Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Link: https://lore.kernel.org/r/20250505094245.2660750-7-quic_amakhija@quicinc.com Signed-off-by: Dmitry Baryshkov dmitry.baryshkov@oss.qualcomm.com Signed-off-by: Sasha Levin sashal@kernel.org ---
**YES** This commit should be backported to stable kernel trees. **Detailed Analysis:** **1. Bug Fix Nature:** The commit fixes a real runtime issue that produces call traces in the boot log. The commit message clearly shows a call trace stack: ``` [ 5.690534] Call trace: [ 5.690536] gpiod_set_value+0x40/0xa4 [ 5.690540] anx7625_runtime_pm_resume+0xa0/0x324 [anx7625] ``` This indicates users are experiencing actual crashes or warnings when using this driver with certain GPIO controllers. **2. Small, Contained Fix:** The code changes are minimal and surgical - only 4 lines changed, replacing `gpiod_set_value()` with `gpiod_set_value_cansleep()` in the `anx7625_power_on()` and `anx7625_power_standby()` functions: - Line 1260: `gpiod_set_value(ctx->pdata.gpio_p_on, 1)` → `gpiod_set_value_cansleep(ctx->pdata.gpio_p_on, 1)` - Line 1263: `gpiod_set_value(ctx->pdata.gpio_reset, 1)` → `gpiod_set_value_cansleep(ctx->pdata.gpio_reset, 1)` - Line 1283: `gpiod_set_value(ctx->pdata.gpio_reset, 0)` → `gpiod_set_value_cansleep(ctx->pdata.gpio_reset, 0)` - Line 1285: `gpiod_set_value(ctx->pdata.gpio_p_on, 0)` → `gpiod_set_value_cansleep(ctx->pdata.gpio_p_on, 0)` **3. Well- Established Pattern:** Looking at the similar commits provided as reference, this exact type of GPIO API fix is common and consistently handles the same underlying issue. All 5 similar commits (marked as "NO" for backport) show the same pattern of switching from `gpiod_set_value()` to `gpiod_set_value_cansleep()` to handle GPIO controllers on message-based buses (I2C/SPI). **4. Technical Correctness:** The fix is technically sound. These functions are called during power management operations (`anx7625_power_on()` and `anx7625_power_standby()`) where sleeping is acceptable and expected. The `_cansleep` variant is the correct API when GPIO controllers might be accessed via slow buses like I2C or SPI. **5. Low Risk:** The change has minimal risk of regression. The `gpiod_set_value_cansleep()` function provides the same functionality as `gpiod_set_value()` but allows sleeping, making it safe to use in contexts where the original was used incorrectly. **6. Critical Subsystem Impact:** This affects the DRM bridge subsystem and display functionality. Users with anx7625 bridge chips connected to I2C GPIO expanders would experience boot-time call traces, which is a user-visible issue that should be fixed in stable kernels. **7. Real Hardware Impact:** The commit specifically mentions "Certain GPIO controllers require access via message-based buses such as I2C or SPI" - this is a real hardware configuration that users deploy, not an edge case. This commit meets all the criteria for stable backporting: it fixes a user-visible bug, has minimal risk, is contained to a single driver, and follows an established pattern for this type of GPIO API fix.
drivers/gpu/drm/bridge/analogix/anx7625.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c index e14c9fdabe2ba..a55e7cfe63243 100644 --- a/drivers/gpu/drm/bridge/analogix/anx7625.c +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c @@ -1257,10 +1257,10 @@ static void anx7625_power_on(struct anx7625_data *ctx) usleep_range(11000, 12000);
/* Power on pin enable */ - gpiod_set_value(ctx->pdata.gpio_p_on, 1); + gpiod_set_value_cansleep(ctx->pdata.gpio_p_on, 1); usleep_range(10000, 11000); /* Power reset pin enable */ - gpiod_set_value(ctx->pdata.gpio_reset, 1); + gpiod_set_value_cansleep(ctx->pdata.gpio_reset, 1); usleep_range(10000, 11000);
DRM_DEV_DEBUG_DRIVER(dev, "power on !\n"); @@ -1280,9 +1280,9 @@ static void anx7625_power_standby(struct anx7625_data *ctx) return; }
- gpiod_set_value(ctx->pdata.gpio_reset, 0); + gpiod_set_value_cansleep(ctx->pdata.gpio_reset, 0); usleep_range(1000, 1100); - gpiod_set_value(ctx->pdata.gpio_p_on, 0); + gpiod_set_value_cansleep(ctx->pdata.gpio_p_on, 0); usleep_range(1000, 1100);
ret = regulator_bulk_disable(ARRAY_SIZE(ctx->pdata.supplies),